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Bad Smell When RV Air Conditioner Is Run

by Ken
(Alberta)

Fixing Bad Smell When RV Air Conditioner Is Running

Fixing Bad Smell When RV Air Conditioner Is Running

I get an almost sewer-type smell when I first use the AC; it is especially noticeable if you go out for a while and then come back in.

ANSWER: Hi Ken, first, I am assuming that your RV has Roof Top Air Conditioners. Here are some things to check on. First, make sure that the filter on your air conditioner is clean. If not it would be a good idea to clean it. Most RV AC filters can be carefully washed in warm water with some mild dish detergent. After washing and rinsing the filter, let it air dry until it is completely dry and reinstall it.

If the filter is torn or will not clean up you should replace the RV Air Conditioner Filter. You should check and clean these filters at least once a month.

Once the filter/s is removed on most RV Air Conditioning units, you will be able to see the evaporator coils. Get a flashlight and look at those coils to see if there is any type of accumulation of dirt or debris present if there is use a very soft bristle vacuum attachment to carefully remove the dust and dirt.

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In the next step, you will have to go up on the roof of your RV. The smell could be coming from the roof unit itself due to a little critter that has gotten into the unit and died or even from stagnant water that is not properly draining from the unit. You will have
to remove the shroud on the air conditioner, which is normally held on with several screws.

Once you have the shroud off, you should inspect the Air Conditioner's interior for any dead critters and clean and remove them as needed. Another area you should inspect is the evaporator drain pan. To get to the drain pan, you may have to remove any cover attached to the evaporator.

Once you access the drain pan, you may see stagnant water that is not draining from the pan. If that is the case, check the drain pan for any blocked drain holes. Also, check to make sure that no one has sealed around the drain holes of the Air Conditioner, thinking they were fixing a leak.

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If none of the above solves the smell problem, then in all likelihood, the smell is coming from a broken Black Water or Grey Water vent pipe inside the RV, or the fumes are coming directly from the vent pipes on the roof of your RV.

Additionally, you should check your RV's house batteries to make sure that they are not overcharging. If they are being overcharged and boiling out, they can produce a bad, rotten egg smell that your AC unit could be circulating around the interior of your RV.

Hope this helps.

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

RVing Al

Comments for Bad Smell When RV Air Conditioner Is Run

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starstarstarstarstar 		What should I do?
by: Nexi

"Additionally, you should check your RV's house batteries to make sure that they are not overcharging. If they are being overcharged and boiling out, they can produce a bad rotten egg smell that your AC unit could be circulating around the interior of your RV."

I am betting that this is our issue since we've been having troubles with our batteries holding a charge. Do we just need to replace the batteries ? How can we prevent this from happening again?
Rating
starstarstarstarstar 		Thank you
by: Anonymous

So helpful. Thank you 🙏
Rating
starstarstarstarstar 		Black water tank vent fumes sucked into ac
by: Jt

why is the fix if the ac is sucking black water tank vent odor/fumes into the rv?
Rating
starstarstarstarstar 		Need better fix
by: Anonymous

We have had two KZ Spree travel trailers, both brand new, a 2012 and a 2014. We have had a terrible a/c odor in each. We were told by our dealer's service department to spray Febreze on the filter, but this is only a very short term fix. Any ideas?
Rating
starstarstarstarstar 		Conditioner smells only one starting up
by: Anonymous

Why does my air conditioner smell only for a little while when it starts up
Rating
starstarstarstarstar 		We just bought a Coleman Mach 3 and it smells horrible
by: Diana

Had it professionally installed 2 days ago. As soon as the ac guy turned it on, I could smell the pugnant air. It seems to be getting worse , rather than better. It has a toxinc/paint like smell.
Few moments ago I called Airxcel company and spoke to the service tech. He denied that the smell is coming from the unit. He sais to get the person who installed it to take a look at the unit, that there may be a dead animal inside. But it doesn't smell like a dead animal. It smells toxic.

I font know what to do . ( And I'm in FL in 90F weather)
Rating
starstarstarstarstar 		AC bad odour
by: Anonymous

We bought a Coleman Mach 3 .
After it was installed and running , there was a bad odour coming from it.
Seems like it's worse when used on high.
It's not close to the vent pipe on the roof.
Sound like we are not the only one having that problem.
But after talking to the company they say they never had that problem.
Really?
Hope we can get some help to solve this problem
Rating
starstarstarstarstar 		Black Water Smell.
by: Motor Home Repair Man

Person with vent by A/C. Buy one of Those Turbo Vent Stacksicon from C.W. or any place on Line. They work Great. No more Smell they spin to the wind direction.

Person with warm air. Need New Units or to ReCharge old. They only last so long. If they sit for more than 6 years. They are usually junk. Need to run them . Like anything else. If you do not use it, It shrivels up and dies.
Rating
starstarstarstarstar 		Rooftop A/C units should not have outside venting
by: Anonymous

Rooftop A/C units should be sealed to the intrusion of outside air. They are inefficient enough without pulling in additional thermal imbalances so if sewer vents are the source then a much closer inspection of the A/C air seals in in order.

The "doughnut" that seals the unit to the roof can be damaged or improperly installed. Likewise, the seals on the internal cover for the indoor air coils should be sealed tight. Often, the sheet metal does not form tightly to the mating surfaces and the sealing tape the factory uses can be too thin to fill in the gaps.

Most of the time, there will develop a coating on the coils that comes from airborne oily residues inside the RV. The cause dust and other organics to adhere to the cooling fins and over time and with a lot of condensation, will rot, giving you much the same smell as the sewer.

This can be adequately cleaned but it is not an easy job and may require removing the unit to do it well. Don't try to use a pressure washer or high pressures to wash the fins and they bend very easily.
Rating
starstarstarstarstar 		ac smells bad when running
by: Anonymous

If it is the black water vent on top of the roof next to the ac how do you stop the smell. Thanks
Rating
starstarstarstarstar 		AC bad smell
by: Anonymous

In our case the smell only occurs when the AC is run and the AC is not putting out cold air. Any suggestions?
Rating
starstarstarstarstar 		Sewer Smell
by: Anonymous

This was happening in our RV but only when we used the air conditioner in our bedroom (it was added on by the previous owner). We finally figured out what the problem was when we climbed on the roof to look at it. The intake for the AC unit was right next to the vent for our black water/sewer so it was pulling in the smell. We only use that unit now if it is extremely hot outside.

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